Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2019
Authors
Jie Zhang Shaoqiang Ni Wenjun Wu Xiao Huang Hongqiang Jiang Qingquan Li Jinnan Wang Guofeng Wu Conrad Zorn Chaoqing YuAbstract
China is continually seeking to improve river water quality. Implemented in 1996, the total pollutant load control system (TPLCS) is a regulatory strategy to reduce total pollutant loads, under which a Pollutant Discharge Permit (PDP) program tracks and regulates nutrient inputs from point source polluters. While this has been promising, the input-response relationship between discharge permits and water quality targets is largely unclear – especially in China's large and complex river basins. In response, this study involved a quantitative analysis method to combine the water quality targets of the 12th Five-Year Plan (2011–2015) with allocated PDPs in the Nenjiang River Basin, China. We demonstrated our approach by applying the Soil and Water Assessment Tool (SWAT) to the Nenjiang River Basin for hydrological and water quality simulation. Ammonia nitrogen (NH3-N) was used as the primary water quality indicator. Modelling indicated that only one control section in the wider river basin did not achieve the water quality target, suggesting that the TPLCS is largely effective. The framework should be applied in other basins to study the effectiveness of PDP policies, advise further updates to the TPLCS, and ultimately aim to achieve freshwater quality targets nationally.
Abstract
The Balaton lake is the focal area of implementing the WFD in Hungary. At present, nutrient loads are primary threat to surface and subsurface water quality in the Balaton watershed. With increasing anthropogenic pressure and increased occurrence of extreme precipitation events in the future the nitrate loads might increase. The goal of this study was to evaluate the combined effect of climate, land use and soil management changes on nitrogen loads in Tetves Creek, which is the tributary of the Balaton lake. We applied the INCA-N (INtegrated CAtchment Model) water quality model to simulate the hydrological processes and nitrate transport for two periods: the current situation (baseline, 2006 to 2015) and for a future period (2046-2055). We calibrated the model against measured discharge and nitrate concentration data. The inorganic nitrogen sub-model was further validated using data of an independent period. The modelling chain was able to reproduce 59% of the variability of average nitrate concentrations in the Tetves Creek for the validation period. After validation, we examined several climate change, land use and nitrogen supply scenarios and their combined effects on runoff and nitrogen loads. Our main conclusions are summarised below.
Authors
Isabella BørjaAbstract
No abstract has been registered
Abstract
Vegetation optical properties have a direct impact on canopy absorption and scattering and are thus needed for modeling surface fluxes. Although plant functional type (PFT) classification varies between different land surface models (LSMs), their optical properties must be specified. The aim of this study is to revisit the “time-invariant optical properties table” of the Simple Biosphere (SiB) model (later referred to as the “SiB table”) presented 30 years ago by Dorman and Sellers (1989), which has since been adopted by many LSMs. This revisit was needed as many of the data underlying the SiB table were not formally reviewed or published or were based on older papers or on personal communications (i.e., the validity of the optical property source data cannot be inspected due to missing data sources, outdated citation practices, and varied estimation methods). As many of today's LSMs (e.g., the Community Land Model (CLM), the Jena Scheme of Atmosphere Biosphere Coupling in Hamburg (JSBACH), and the Joint UK Land Environment Simulator (JULES)) either rely on the optical properties of the SiB table or lack references altogether for those they do employ, there is a clear need to assess (and confirm or correct) the appropriateness of those being used in today's LSMs. Here, we use various spectral databases to synthesize and harmonize the key optical property information of PFT classification shared by many leading LSMs. For forests, such classifications typically differentiate PFTs by broad geo-climatic zones (i.e., tropical, boreal, temperate) and phenology (i.e., deciduous vs. evergreen). For short-statured vegetation, such classifications typically differentiate between crops, grasses, and photosynthetic pathway. Using the PFT classification of the CLM (version 5) as an example, we found the optical properties of the visible band (VIS; 400–700 nm) to fall within the range of measured values. However, in the near-infrared and shortwave infrared bands (NIR and SWIR; e.g., 701–2500 nm, referred to as “NIR”) notable differences between CLM default and measured values were observed, thus suggesting that NIR optical properties are in need of an update. For example, for conifer PFTs, the measured mean needle single scattering albedo (SSA, i.e., the sum of reflectance and transmittance) estimates in NIR were 62 % and 78 % larger than the CLM default parameters, and for PFTs with flat leaves, the measured mean leaf SSA values in NIR were 20 %, 14 %, and 19 % larger than the CLM defaults. We also found that while the CLM5 PFT-dependent leaf angle values were sufficient for forested PFTs and grasses, for crop PFTs the default parameterization appeared too vertically oriented, thus warranting an update. In addition, we propose using separate bark reflectance values for conifer and deciduous PFTs and demonstrate how shoot-level clumping correction can be incorporated into LSMs to mitigate violations of turbid media assumption and Beer's law caused by the nonrandomness of finite-sized foliage elements.
Authors
Rodrigo B. Onofre G. A. Ortiz P. P. de Mello Neto David M. Gadoury Arne Stensvand Mark Rea Andrew Bierman Natalia A. PeresAbstract
No abstract has been registered
Authors
Arohi Srivastava Sharad Mohan Tim H. Mauchline Keith DaviesAbstract
Pasteuria spp. belong to a group of genetically diverse endospore-forming bacteria (phylum: Firmicutes) that are known to parasitize plant-parasitic nematodes and water fleas (Daphnia spp.). Collagen-like fibres form the nap on the surface of endospores and the genes encoding these sequences have been hypothesised to be involved in the adhesion of the endospores of Pasteuria spp. to their hosts. We report a group of 17 unique collagen-like genes putatively encoded by Pasteuria penetrans (strain: Res148) that formed five different phylogenetic clusters and suggest that collagen-like proteins are an important source of genetic diversity in animal pathogenic Firmicutes including Pasteuria. Additionally, and unexpectedly, we identified a putative collagen-like sequence which had a very different sequence structure to the other collagen-like proteins but was similar to the protein sequences in Megaviruses that are involved in host-parasite interactions. We, therefore, suggest that these diverse endospore surface proteins in Pasteuria are involved in biological functions, such as cellular adhesion; however, they are not of monophyletic origin and were possibly obtained de novo by mutation or possibly through selection acting upon several historic horizontal gene transfer events.
Abstract
The blacktip shark Carcharhinus limbatus is a cosmopolitan species found in warm-temperate, subtropical and tropical waters around the world. The research here aimed to assess whether multiple paternity exists in South African C. limbatus and to confirm phylogeographic patterns previously observed within the species. A minimum and maximum frequency of 50% and 71% multiple paternity, respectively, were observed in 14 litters genotyped with five microsatellite markers. Based on the mitochondrial control region, relatively high nucleotide and haplotype diversity characterised the South African sampling population, and pairwise φST values indicated that it significantly differed from the populations of the Pacific and the western Atlantic oceans. The haplotype network showed that the South African samples were grouped closely with the Australian, Indo-Pacific and West African C. limbatus samples, which is suggestive of an Indo-Pacific origin for this population. This study is the first to report multiple paternity in this species. Furthermore, the results reveal that C. limbatus from South Africa is genetically diverse and phylogeographically distinct from most other C. limbatus populations.
Abstract
No abstract has been registered
Authors
Morten Lillemo Selamawit Tekle Espen Sannes Sørensen Trond Buraas Heidi Udnes Aamot Ingerd Skow Hofgaard Bernd Rodemann Alf Ceplitis Helge Skinnes Åsmund BjørnstadAbstract
No abstract has been registered
Abstract
No abstract has been registered